This invention relates to connector-terminal assemblies and more particularly to a specialized connector assembly adapted to pass electrical current through a furnace firewall and to operate under the extreme temperatures associated therewith.
There is a substantial need for electrical connectors which can function under the high temperatures commonly found in the furnace and heater art. The use of insulated connectors in electric furnaces and heaters, whether made for residential, commercial, or industrial uses, is widely known. However, the need also exists for the use of insulated connectors in furnaces fueled by other means.
Heretofore, connector-terminal assemblies suitable for installation through a furnace or heater firewall have included a two-piece insulator built around a threaded rod connector. Typically, a first piece of the insulation fits in a rectangular hole in the firewall and abuts one side of the wall adjacent the hole. The second piece of insulation fits over the portion of the first piece of insulation extending through the hole and abuts the opposing side of the wall adjacent the hole. Both pieces of insulation include a central hole therethrough in which the threaded rod is positioned. The threaded rod connector includes a square nut soldered thereon. The nut is nested in a rectangular cut-out portion in the first piece of insulation adjacent the outer end of the central hole for preventing the threaded rod from rotating therein. The threaded ends of the connector rod are utilized as terminals for conductors which may be fastened thereon. Typically, nuts and lock washers are fitted on the opposing ends. When tightened, one of the opposing nuts and the square nut maintain the entire assembly in mounted position on the firewall.
This prior art connector has several drawbacks. First, if a terminal on the connector is loosened to remove or replace a conductor, the entire assembly may become loose and unstable because the means for tightening at least one of the terminals is also the means for keeping the assembly mounted on the firewall. Second, when the opposed terminals are tightened, the two-piece insulator is positioned in compressive stress. As the furnace heats up, the insulator expands, and additional, potentially dangerous stress is built up in both the insulator pieces and the connector. The stress in the connector is tensile stress.
It is therefore a general object of the invention to provide an improved connector-terminal assembly constructed in accordance with the invention.
Another object of the invention is to provide a connector-terminal assembly for mounting through a furnace firewall hole utilizing a one-piece insulator which is free of compressive stress as mounted through the firewall.
Another object of the invention is to provide a connector assembly for furnace installation wherein the means for anchoring the insulator to a furnace firewall hole is structurally independent from the means for fastening conductors on the connector.